Mercedes-Benz SL launches don't come around often. As you can tell by the spectacular piece of metal on today's cover, the nameplate has been around for a long, long time - but in that six-decade stretch there have been only a handful of different models.

The newest model has actually made a move back towards the SLs of old. SL means 'Super Light', which has been a bit of a misnomer in recent times - and the latest version has shed many kilograms to become a veritable rocketship, albeit one decked out with great technology, comfort and a twin-turbo V8 that'll rattle your bones.

Mercedes New Zealand has elected to eschew the six-cylinder-toting SL350, so we didn't drive it on last week's launch event in Victoria, and instead concentrated on the powerhouse SL500 we'll get.

The smaller version may be available down the track, but Kiwi buyers have a tendency to aim for the sharp end of the range - the SL500 or the fire-breathing AMG recently featured in Driven is always going to be a better option on a Herne Bay driveway.

Of course, if you really don't like the wild combination of power and torque, your Benz dealer might be able to secure the wee six-pot version - you could get a matching handbag.

Roadsters like the SL have really come into their own since the wonders of folding hard tops have blessed the droptop motoring world. While Kiwi weather is lovely on the odd occasion, our "four seasons in one day" meteorological mystery can see convertible owners avoiding things like red lights and traffic to guarantee they keep themselves dry. But the mechanical genius that turns the SL from stunning roofless roadster to stylish low-slung coupe is a 19-second exercise - and while the process can't take place when you're moving over 7km/h (roof-sized bits of metal aren't aerodynamic enough, says Mercedes), it can be kicked off as you slow at an intersection.

Wind in the hair motoring does have a certain romance about it, but when your ears are bright red from cold and your teeth are chattering, romantic notions quickly give way to clever plans to thaw your head out. The tech wizardry that the new SL has on board works to get rid of this issue - an "air scarf" blows hot air around your neck, there's an electronic draught-stopping blink that rises behind the seats at the push of a button. Add seat warmers and highly effective climate air and New Zealand convertible dramas are averted. Failing that, a spare 19 seconds will solve it.

In either top up or top down mode, the SL is a stunning piece of machinery that has always sported a fairly timeless design. Even the boxy old SLs of the 1980s have an understated cool about them.

The new one doesn't stand out like a ginger throwback in the family photo - it's a bigger car, stretching 50mm to 4612mm long; and another 57mm width adding up to 1877mm. This is a behemoth, dimensionally, but once behind the wheel its perceived mass seems to disappear, the only remaining clue the expanse of bonnet that gently curves away from view - not really an issue for nose-nervous drivers. If you're going to hit something the clever Benz jams on the brakes, as we discovered during our Auckland traffic-style escape from the Melbourne CBD.

The 256kg all-aluminium body (a first on a Merc road car) has added to the 500SL's torsional rigidity - the company claims it's 20 per cent tighter - and dropped an impressive 125kg of heft to make its overall weight just 1785kg. While this isn't Super Light in, say, Lotus terms, for a huge Mercedes-Benz with a V8 under its hood it's positively featherweight.

Once you point this lengthy roadster to the hills, it really comes into its own. The Blue Efficiency 4.7LV8 with a turbo strapped to each bank of cylinders makes a hefty 320kW and 700Nm of torque, which is more than the last-generation SL63 AMG.

Those concerned about the green credentials of such a show-off machine will be pleased to note that there are some Eco modes added to the package, including a fairly non-invasive stop/start system that, while effective, does restart every time you lift off the brake. It makes quietly rolling forward a bit of strange affair. It uses a factory claimed 9.4L/100km of fuel on a combined cycle, which was only a litre or so less than the car read-out after our enthusiastic jaunt around AFL country. Its CO2 output is 218g/km.

There are a trio of performance settings, which have a bearing on outright grunt, how the 7G-Tronic Plus seven-speed transmission feeds power to the road, and how the steering and steering feel is relayed to the driver. Pushing along in eco or comfort modes carved a bit of the outright urgency out of the car, but comfort was certainly a good compromise on the Victorian country roads, which threw up holes, dodgy camber and surface swaps with almost monotonous regularity - and these were a definite improvement on most of New Zealand's rural delivery routes.

Sport mode, however, was just about driving joy. The SL is, by no means, a pure drivers' car - that's the domain of Porsche 911s and their ilk. But it is a bitumen weapon with a racing pedigree that it has never really let go - and offers an awe-inspiring burst of acceleration when the pedal is decked.

The 0-100km/h sprint time is a shade over 4.5 seconds, and it has been noted that the upshift from fourth to fifth at 200km/h with the auto locked in manual mode still leaves a couple of hundred revs to spare - not something particularly necessary to this story, but nice to know. If there's one criticism of the 500, it's that its engine note doesn't grab you by the lugs, even in sport mode.

But let loose, even on dicey roads, and the SL is surprisingly nimble - it's still screamingly obvious that it's got a bit of weight, but the whopping 285-wide 19-inch feet on the back end do help reign things in, and a very accurate steering rack belies the car's sheer size. Passing moves are, not surprisingly, very easy to put on SL trips the light fantastic

almost any other vehicle on the road, and while it's very easy to get a bit too enthusiastic velocity-wise, the well-developed cruise control system will accelerate and brake to keep to the preset pace. Tapping a stick mounted low on the left side of the steering column can add or remove speed in increments of 10km or less.

There's one last trick that Mercedes is particularly pleased with, called Magic Vision Control. It isn't quite as mystical as last year's SLK-pioneered Magic Sky, the glass roof that can be turned from opaque to transparent at the push of a button, and is available as an option, but Magic Vision Control is effective.

It pipes water directly through the windscreen wiper arms, and squirts it ahead of the sweeping blade in its direction of travel. Sure, David Copperfield would scoff at this, but it does clean the screen with very German levels of efficiency, won't send most of your washer bottle in a wide arc on to the bonnet of the car behind, and saves almost half the water that you'd usually go through.

Magic tricks and all, the SL500 in base form arrives in New Zealand wearing a sticker price of $265,000 - and it's worth noting that is significantly cheaper than for our Transtasman pals, who are hit by both GST and the laughable luxury car tax.